There have been proposed apparatuses configured to include a first connecting part and a second connecting part to be connected to each other, thereby forming a propagation channel therebetween for laser beam from a laser light source to propagate therethrough, as those disclosed in Japanese Patent Application Laid-Open No. 2004-260027, for example.
In Japanese Patent Application Laid-Open No. 2004-260027, the first connecting part such as a first optical connector 12 and the second connecting part such as a third optical connector 41 are connected to each other to form a propagation channel therebetween allowing laser beam from a laser light source to propagate therethrough. In this structure, when the connection between the first and second connecting parts is released, the output of the laser beam can be terminated.
When such laser beam is used for illumination purpose, the output of such laser beam is required to be within a permissible exposure time (as illustrated in FIG. 4) from the viewpoint of safety (equal to or lower than class 2 in accordance with JIS C 6802). The apparatus disclosed in Japanese Patent Application Laid-Open No. 2004-260027 requires substantial time (μs order or longer) from the release of the connection between the first and second connecting parts to the termination of the output of the laser beam. Therefore, during the time from the release of the connection between the first and second connecting parts to the termination of the output of the laser beam, it is difficult for the apparatus to be controlled so that the output of laser beam from the first or second connecting part is within the permissible exposure time.
Note that the reason why there is required a substantial time till the termination of the output of the laser beam is as follows. Such a time period from the release of the connection between the first and second connecting parts to the termination of the output of the laser beam is required for executing process by a software (program) for controlling a plurality of circuits and actual processes performed by the respective circuits. The circuits may include an optical connector connection determination circuit, a light-reception termination determination circuit, a light-reception termination signal transmitting circuit, a light-reception termination signal receiving circuit, and a laser emission shutoff circuit, which will be collectively referred to as a “shutoff control circuit” hereinafter.